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qdio: extend API to allow polling

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Extend the qdio API to allow polling in the upper-layer driver. This
is needed by qeth to use NAPI.

To use the new interface the upper-layer driver must specify the
queue_start_poll(). This callback is used to signal the upper-layer
driver that is has initiative and must process the inbound queue by
calling qdio_get_next_buffers(). If the upper-layer driver wants to
stop polling it calls qdio_start_irq().

Since adapter interrupts are not completely stoppable qdio implements
a software bit QDIO_QUEUE_IRQS_DISABLED to safely disable interrupts for an
input queue.

The old interface is preserved and will be used as is by zfcp.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jan Glauber 2010-09-07 21:14:39 +00:00 committed by David S. Miller
parent e508be174a
commit d36deae750
7 changed files with 226 additions and 62 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
arch/s390/include/asm/qdio.h
View file

@ -360,6 +360,7 @@ struct qdio_initialize {
unsigned int no_output_qs;
qdio_handler_t *input_handler;
qdio_handler_t *output_handler;
void (*queue_start_poll) (struct ccw_device *, int, unsigned long);
unsigned long int_parm;
void **input_sbal_addr_array;
void **output_sbal_addr_array;
@ -377,11 +378,13 @@ struct qdio_initialize {
extern int qdio_allocate(struct qdio_initialize *);
extern int qdio_establish(struct qdio_initialize *);
extern int qdio_activate(struct ccw_device *);
extern int do_QDIO(struct ccw_device *cdev, unsigned int callflags,
int q_nr, unsigned int bufnr, unsigned int count);
extern int qdio_shutdown(struct ccw_device*, int);
extern int do_QDIO(struct ccw_device *, unsigned int, int, unsigned int,
unsigned int);
extern int qdio_start_irq(struct ccw_device *, int);
extern int qdio_stop_irq(struct ccw_device *, int);
extern int qdio_get_next_buffers(struct ccw_device *, int, int *, int *);
extern int qdio_shutdown(struct ccw_device *, int);
extern int qdio_free(struct ccw_device *);
extern int qdio_get_ssqd_desc(struct ccw_device *dev, struct qdio_ssqd_desc*);
extern int qdio_get_ssqd_desc(struct ccw_device *, struct qdio_ssqd_desc *);
#endif /* __QDIO_H__ */

29
drivers/s390/cio/qdio.h
View file

@ -208,6 +208,7 @@ struct qdio_dev_perf_stat {
unsigned int eqbs_partial;
unsigned int sqbs;
unsigned int sqbs_partial;
unsigned int int_discarded;
} ____cacheline_aligned;
struct qdio_queue_perf_stat {
@ -222,6 +223,10 @@ struct qdio_queue_perf_stat {
unsigned int nr_sbal_total;
};
enum qdio_queue_irq_states {
QDIO_QUEUE_IRQS_DISABLED,
};
struct qdio_input_q {
/* input buffer acknowledgement flag */
int polling;
@ -231,6 +236,10 @@ struct qdio_input_q {
int ack_count;
/* last time of noticing incoming data */
u64 timestamp;
/* upper-layer polling flag */
unsigned long queue_irq_state;
/* callback to start upper-layer polling */
void (*queue_start_poll) (struct ccw_device *, int, unsigned long);
};
struct qdio_output_q {
@ -399,6 +408,26 @@ static inline int multicast_outbound(struct qdio_q *q)
#define sub_buf(bufnr, dec) \
((bufnr - dec) & QDIO_MAX_BUFFERS_MASK)
#define queue_irqs_enabled(q) \
(test_bit(QDIO_QUEUE_IRQS_DISABLED, &q->u.in.queue_irq_state) == 0)
#define queue_irqs_disabled(q) \
(test_bit(QDIO_QUEUE_IRQS_DISABLED, &q->u.in.queue_irq_state) != 0)
#define TIQDIO_SHARED_IND 63
/* device state change indicators */
struct indicator_t {
u32 ind; /* u32 because of compare-and-swap performance */
atomic_t count; /* use count, 0 or 1 for non-shared indicators */
};
extern struct indicator_t *q_indicators;
static inline int shared_ind(struct qdio_irq *irq_ptr)
{
return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
}
/* prototypes for thin interrupt */
void qdio_setup_thinint(struct qdio_irq *irq_ptr);
int qdio_establish_thinint(struct qdio_irq *irq_ptr);

33
drivers/s390/cio/qdio_debug.c
View file

@ -56,9 +56,16 @@ static int qstat_show(struct seq_file *m, void *v)
seq_printf(m, "DSCI: %d nr_used: %d\n",
*(u32 *)q->irq_ptr->dsci, atomic_read(&q->nr_buf_used));
seq_printf(m, "ftc: %d last_move: %d\n", q->first_to_check, q->last_move);
seq_printf(m, "polling: %d ack start: %d ack count: %d\n",
q->u.in.polling, q->u.in.ack_start, q->u.in.ack_count);
seq_printf(m, "ftc: %d last_move: %d\n",
q->first_to_check, q->last_move);
if (q->is_input_q) {
seq_printf(m, "polling: %d ack start: %d ack count: %d\n",
q->u.in.polling, q->u.in.ack_start,
q->u.in.ack_count);
seq_printf(m, "IRQs disabled: %u\n",
test_bit(QDIO_QUEUE_IRQS_DISABLED,
&q->u.in.queue_irq_state));
}
seq_printf(m, "SBAL states:\n");
seq_printf(m, "|0 |8 |16 |24 |32 |40 |48 |56 63|\n");
@ -113,22 +120,6 @@ static int qstat_show(struct seq_file *m, void *v)
return 0;
}
static ssize_t qstat_seq_write(struct file *file, const char __user *buf,
size_t count, loff_t *off)
{
struct seq_file *seq = file->private_data;
struct qdio_q *q = seq->private;
if (!q)
return 0;
if (q->is_input_q)
xchg(q->irq_ptr->dsci, 1);
local_bh_disable();
tasklet_schedule(&q->tasklet);
local_bh_enable();
return count;
}
static int qstat_seq_open(struct inode *inode, struct file *filp)
{
return single_open(filp, qstat_show,
@ -139,7 +130,6 @@ static const struct file_operations debugfs_fops = {
.owner = THIS_MODULE,
.open = qstat_seq_open,
.read = seq_read,
.write = qstat_seq_write,
.llseek = seq_lseek,
.release = single_release,
};
@ -166,7 +156,8 @@ static char *qperf_names[] = {
"QEBSM eqbs",
"QEBSM eqbs partial",
"QEBSM sqbs",
"QEBSM sqbs partial"
"QEBSM sqbs partial",
"Discarded interrupts"
};
static int qperf_show(struct seq_file *m, void *v)

138
drivers/s390/cio/qdio_main.c
View file

@ -884,8 +884,19 @@ static void qdio_int_handler_pci(struct qdio_irq *irq_ptr)
if (unlikely(irq_ptr->state == QDIO_IRQ_STATE_STOPPED))
return;
for_each_input_queue(irq_ptr, q, i)
tasklet_schedule(&q->tasklet);
for_each_input_queue(irq_ptr, q, i) {
if (q->u.in.queue_start_poll) {
/* skip if polling is enabled or already in work */
if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
&q->u.in.queue_irq_state)) {
qperf_inc(q, int_discarded);
continue;
}
q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
q->irq_ptr->int_parm);
} else
tasklet_schedule(&q->tasklet);
}
if (!(irq_ptr->qib.ac & QIB_AC_OUTBOUND_PCI_SUPPORTED))
return;
@ -1519,6 +1530,129 @@ int do_QDIO(struct ccw_device *cdev, unsigned int callflags,
}
EXPORT_SYMBOL_GPL(do_QDIO);
/**
* qdio_start_irq - process input buffers
* @cdev: associated ccw_device for the qdio subchannel
* @nr: input queue number
*
* Return codes
* 0 - success
* 1 - irqs not started since new data is available
*/
int qdio_start_irq(struct ccw_device *cdev, int nr)
{
struct qdio_q *q;
struct qdio_irq *irq_ptr = cdev->private->qdio_data;
if (!irq_ptr)
return -ENODEV;
q = irq_ptr->input_qs[nr];
WARN_ON(queue_irqs_enabled(q));
if (!shared_ind(q->irq_ptr))
xchg(q->irq_ptr->dsci, 0);
qdio_stop_polling(q);
clear_bit(QDIO_QUEUE_IRQS_DISABLED, &q->u.in.queue_irq_state);
/*
* We need to check again to not lose initiative after
* resetting the ACK state.
*/
if (!shared_ind(q->irq_ptr) && *q->irq_ptr->dsci)
goto rescan;
if (!qdio_inbound_q_done(q))
goto rescan;
return 0;
rescan:
if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
&q->u.in.queue_irq_state))
return 0;
else
return 1;
}
EXPORT_SYMBOL(qdio_start_irq);
/**
* qdio_get_next_buffers - process input buffers
* @cdev: associated ccw_device for the qdio subchannel
* @nr: input queue number
* @bufnr: first filled buffer number
* @error: buffers are in error state
*
* Return codes
* < 0 - error
* = 0 - no new buffers found
* > 0 - number of processed buffers
*/
int qdio_get_next_buffers(struct ccw_device *cdev, int nr, int *bufnr,
int *error)
{
struct qdio_q *q;
int start, end;
struct qdio_irq *irq_ptr = cdev->private->qdio_data;
if (!irq_ptr)
return -ENODEV;
q = irq_ptr->input_qs[nr];
WARN_ON(queue_irqs_enabled(q));
qdio_sync_after_thinint(q);
/*
* The interrupt could be caused by a PCI request. Check the
* PCI capable outbound queues.
*/
qdio_check_outbound_after_thinint(q);
if (!qdio_inbound_q_moved(q))
return 0;
/* Note: upper-layer MUST stop processing immediately here ... */
if (unlikely(q->irq_ptr->state != QDIO_IRQ_STATE_ACTIVE))
return -EIO;
start = q->first_to_kick;
end = q->first_to_check;
*bufnr = start;
*error = q->qdio_error;
/* for the next time */
q->first_to_kick = end;
q->qdio_error = 0;
return sub_buf(end, start);
}
EXPORT_SYMBOL(qdio_get_next_buffers);
/**
* qdio_stop_irq - disable interrupt processing for the device
* @cdev: associated ccw_device for the qdio subchannel
* @nr: input queue number
*
* Return codes
* 0 - interrupts were already disabled
* 1 - interrupts successfully disabled
*/
int qdio_stop_irq(struct ccw_device *cdev, int nr)
{
struct qdio_q *q;
struct qdio_irq *irq_ptr = cdev->private->qdio_data;
if (!irq_ptr)
return -ENODEV;
q = irq_ptr->input_qs[nr];
if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
&q->u.in.queue_irq_state))
return 0;
else
return 1;
}
EXPORT_SYMBOL(qdio_stop_irq);
static int __init init_QDIO(void)
{
int rc;

1
drivers/s390/cio/qdio_setup.c
View file

@ -161,6 +161,7 @@ static void setup_queues(struct qdio_irq *irq_ptr,
setup_queues_misc(q, irq_ptr, qdio_init->input_handler, i);
q->is_input_q = 1;
q->u.in.queue_start_poll = qdio_init->queue_start_poll;
setup_storage_lists(q, irq_ptr, input_sbal_array, i);
input_sbal_array += QDIO_MAX_BUFFERS_PER_Q;

68
drivers/s390/cio/qdio_thinint.c
View file

@ -25,24 +25,20 @@
*/
#define TIQDIO_NR_NONSHARED_IND 63
#define TIQDIO_NR_INDICATORS (TIQDIO_NR_NONSHARED_IND + 1)
#define TIQDIO_SHARED_IND 63
/* list of thin interrupt input queues */
static LIST_HEAD(tiq_list);
DEFINE_MUTEX(tiq_list_lock);
/* adapter local summary indicator */
static unsigned char *tiqdio_alsi;
static u8 *tiqdio_alsi;
/* device state change indicators */
struct indicator_t {
u32 ind; /* u32 because of compare-and-swap performance */
atomic_t count; /* use count, 0 or 1 for non-shared indicators */
};
static struct indicator_t *q_indicators;
struct indicator_t *q_indicators;
static int css_qdio_omit_svs;
static u64 last_ai_time;
static inline unsigned long do_clear_global_summary(void)
{
register unsigned long __fn asm("1") = 3;
@ -116,59 +112,73 @@ void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
}
}
static inline int shared_ind(struct qdio_irq *irq_ptr)
static inline int shared_ind_used(void)
{
return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
return atomic_read(&q_indicators[TIQDIO_SHARED_IND].count);
}
/**
* tiqdio_thinint_handler - thin interrupt handler for qdio
* @ind: pointer to adapter local summary indicator
* @drv_data: NULL
* @alsi: pointer to adapter local summary indicator
* @data: NULL
*/
static void tiqdio_thinint_handler(void *ind, void *drv_data)
static void tiqdio_thinint_handler(void *alsi, void *data)
{
struct qdio_q *q;
last_ai_time = S390_lowcore.int_clock;
/*
* SVS only when needed: issue SVS to benefit from iqdio interrupt
* avoidance (SVS clears adapter interrupt suppression overwrite)
* avoidance (SVS clears adapter interrupt suppression overwrite).
*/
if (!css_qdio_omit_svs)
do_clear_global_summary();
/*
* reset local summary indicator (tiqdio_alsi) to stop adapter
* interrupts for now
*/
xchg((u8 *)ind, 0);
/* reset local summary indicator */
if (shared_ind_used())
xchg(tiqdio_alsi, 0);
/* protect tiq_list entries, only changed in activate or shutdown */
rcu_read_lock();
/* check for work on all inbound thinint queues */
list_for_each_entry_rcu(q, &tiq_list, entry)
/* only process queues from changed sets */
if (*q->irq_ptr->dsci) {
qperf_inc(q, adapter_int);
list_for_each_entry_rcu(q, &tiq_list, entry) {
/* only process queues from changed sets */
if (!*q->irq_ptr->dsci)
continue;
if (q->u.in.queue_start_poll) {
/* skip if polling is enabled or already in work */
if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
&q->u.in.queue_irq_state)) {
qperf_inc(q, int_discarded);
continue;
}
/* avoid dsci clear here, done after processing */
q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
q->irq_ptr->int_parm);
} else {
/* only clear it if the indicator is non-shared */
if (!shared_ind(q->irq_ptr))
xchg(q->irq_ptr->dsci, 0);
/*
* don't call inbound processing directly since
* that could starve other thinint queues
* Call inbound processing but not directly
* since that could starve other thinint queues.
*/
tasklet_schedule(&q->tasklet);
}
qperf_inc(q, adapter_int);
}
rcu_read_unlock();
/*
* if we used the shared indicator clear it now after all queues
* were processed
* If the shared indicator was used clear it now after all queues
* were processed.
*/
if (atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) {
if (shared_ind_used()) {
xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
/* prevent racing */

6
drivers/s390/scsi/zfcp_qdio.c
View file

@ -277,16 +277,12 @@ int zfcp_qdio_send(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
static void zfcp_qdio_setup_init_data(struct qdio_initialize *id,
struct zfcp_qdio *qdio)
{
memset(id, 0, sizeof(*id));
id->cdev = qdio->adapter->ccw_device;
id->q_format = QDIO_ZFCP_QFMT;
memcpy(id->adapter_name, dev_name(&id->cdev->dev), 8);
ASCEBC(id->adapter_name, 8);
id->qib_rflags = QIB_RFLAGS_ENABLE_DATA_DIV;
id->qib_param_field_format = 0;
id->qib_param_field = NULL;
id->input_slib_elements = NULL;
id->output_slib_elements = NULL;
id->no_input_qs = 1;
id->no_output_qs = 1;
id->input_handler = zfcp_qdio_int_resp;